The Florida State golfer had just finished his second 18 holes at a U.S. Open sectional qualifier June 8 at the Bear's Club in Jupiter. He had shot another 2-under 70 for a 36-hole total of 4-under 140. Then came the wait to see if his score was good enough to earn one of the qualifier's four U.S. Open spots from the field of 70.

"I just kept checking my phone and hitting refresh," said Maguire, 20, a St. Petersburg High alumnus. "It was a long hour and a half."

PGA Tour player Luke Donald, who won the 2012 Transitions Championship at Innisbrook in Palm Harbor, matched Maguire with 140, the best score in the field. Web.com Tour player Andrew Pope did the same.

The only two threats still on the course were Maguire's FSU teammate Cristobal Del Solar and Sam Horsfield, a junior golf sensation who has committed to Florida. If both those players birdied their final holes, there would be a five-way tie for the four spots.

"When Sam parred the final hole, I knew that I was in," Maguire said. "It was a huge sense of relief."

Horsfield beat Del Solar in a two-hole playoff to earn the fourth spot for the U.S. Open, which begins today at Chambers Bay in University Place, Wash., outside Seattle.

For Maguire, who recently completed his sophomore year at FSU, this is his first major tournament. A high school state champion in 2013, he was the ACC freshman of the year in 2014. He is coming off a tie for 22nd at the NCAA Championship on June 1 in Bradenton.

Maguire was exempt from playing in the first round of U.S. Open qualifying. He said he knew anything could happen in a one-day, 36-hole pressure cooker that is the final round of qualifying — which was held at 10 sites — but he felt good about his chances.

"I've been playing well coming into qualifying," Maguire said. "I knew that if I played smart, didn't make any mistakes that would lead to a big number, then I would have a chance. People asked me what my summer plans were, and I told them that playing in the U.S. Open was a big possibility."

The day after Maguire qualified, he was off to Chicago to play in the Palmer Cup, a Ryder Cup-style tournament for college players. A team from the United States played a team from Europe in the three-day tournament and won 18-12.

On Sunday night, Maguire left for Washington to begin his U.S. Open week.

When Maguire tees off today with playing partners Joshua Persons and John Parry, he said he was sure he would be nervous. Maguire had never played Chambers Bay before he had a few practice rounds this week.

Maguire — who had played the Bear's Club just once before the U.S. Open qualifier — said he is most looking forward to the experience.

And he is aiming high.

"The big test for me is how I'm going to be able to handle the pressure of a tournament like this," Maguire said. "I've played in big tournaments but nothing as big as this. But I think I'll be okay. My goal is to make the cut and play on the weekend. And then if I do that, I hope to get myself in contention."

Maguire said he will return to Florida State for his junior year. After that, it appears a professional career is in his future.